Honeywell R7426B User Manual

PRODUCT DATA
63- 2565
® U.S. Registered Trademark
Copyright © 2000 Honeywell Inc. • All Rights Reserved
R7426A,B,C,D
Temperature and
Universal Input Controllers
TIME-INDEPENDENT CONTROLLERS
APPLICATION
R7426A,B,C Temperature Controllers use direct digital control
technology to provide more accurate and efficient operation of
heating, ventilation and air conditioning (HVAC) systems.
Parameters are preset for plug and play operation and provide
different control strategies for optimum system performance.
The controller performs proportional or proportional plus
integral (P+I) control and covers all space, supply air or water
flow applications within the specified ranges of 32°F to 122°F
(0°C to 50°C) or 32°F to 266°F (0°C to 130°C). Standard
Pt 1000 or NTC 20K ohm temperature sensors can be used.
The modern design with its easy to operate user interface and
LCD allows complete flexibility of control system design,
accurate parameter setting, and display of actual temperature
values, setpoints and outputs.
The R7426D Universal Input Controller covers all space or
discharge air humidity control applications and special
applications, such as pressure control, within 0 to 10 Vdc input
ranges. The controller provides input span adjustment to
match the transmitter output specification.
FEATURES
• Selectable proportional, proportional plus integral
(P+I), or (R7426D only) proportional plus integral plus
derivative (P+I+D) control.
• Pre-programmed control parameters.
• Digital parameter setting.
• Selectable direct/reverse acting output.
• 24 Vac power supply.
R7426A,B,C
• 3 inputs for temperature sensors.
• Automatic sensor type identification of Pt 1000 or
NTC 20K ohm.
• 3 digital inputs for plant/system On/Off, occupancy
(alternatively summer/winter changeover) and freeze
protection.
• Dehumidification control via humidity deviation input.
• Selectable floating output functions:
— Floating.
— 2, 3, 4, 6 or 15 stage On/Off (TRIAC).
— Pulse width modulation (PWM).
• Analog outputs 0/2 to 10Vdc selectable.
• Start-up routine.
• Space/supply limit or cascade control.
• Sequence control of heating, mixed air damper or
energy recovery system and cooling.
R7426D
• 2 analog inputs 0 to 10Vdc for transmitters.
• Control output monitoring and manual output signal
override.
• Master/submaster cascade control.
• Main variable control and optional high/low limit control.
• Input span adjustment.
• Temperature compensation input.
• Optional remote setpoint adjustment.
Contents
Application ....................................................................... 1
Features ........................................................................... 1
Specifications ................................................................... 2
Ordering Information ........................................................ 2
Installation ........................................................................ 3
Operation ......................................................................... 4
Operating Overview ......................................................... 8
Appendix .......................................................................... 10
Control And Configuration Parameters ....................... 10
Parameter Details ....................................................... 12

Honeywell R7426B Specifications

General

Brand	Honeywell
Model	R7426B
Category	Controller
Language	English